This invention relates to a circular saw for stony materials comprising a peripheral rim provided around its circumference with cutting elements, a composite core of which the lateral faces are covered by two annular discs equal in diameter of thin plate assembled by bonding under pressure and of which the centre is provided with a central ring for mounting on a drive shaft.
The main application of the invention is in the manufacture of lightweight, low-noise sawing discs which, despite their thinness, show excellent resistance to deflection during the sawing operation.
DE-AS No. 1 042 874 relates to a low-noise circular saw for stony materials. The core comprises two thin annular metal discs equal in diameter which are disposed coaxially on either side of a sheet of vibration-absorbing material. These discs are joined firmly to one another by bonding under pressure. The interposition of the absorbing sheet reduces or even eliminates the noise generated by the interaction of the cutting elements and the stony material during application of the cutting force.
Unfortunately, this saw has the disadvantage of inadequate static and dynamic strength because it undergoes unacceptable cutting deflections during the sawing of hard stony materials.
Similarly, Belgian Patent application No. 0/168.557 relates to a circular saw capable of absorbing lateral stresses and of making a straight cut.
This saw consists of two symmetrical discs of thin steel plate stamped into the shape of saucers. In the first embodiment, the discs are joined back-to-back so as to form a biconcave circular saw of which the splayed edges are held apart by a spacer ring. In a second embodiment, the discs are joined face-to-face to form a bevelled tool of which the central part is hollow. The empty space between the discs is filled with a vibration-absorbing material.
Although this embodiment makes the saw stronger, it does not make it any lighter. In addition, the circular saw thus obtained has a core of which the thickness is substantially equal to that of conventional discs. Accordingly, it does not enable the losses of material during sawing to be reduced.